The present invention relates to an observing equipment such as a binocular, a monocular, or a terrestrial telescope that has a hand-vibration compensation system.
Recently, binoculars provided with hand-vibration compensation systems for compensating trembling of image due to the hand-vibration have been developed. An example of the conventional hand-vibration compensation system for a binocular includes a variable angle prism which is controlled to change the angle so that trembling of image is cancelled. Such a compensation system is, however, relatively difficult to manufacture and to control.
In a field of cameras, a hand-vibration compensation optical system including compensation lens, which is to be moved within an optical path, has been suggested. If such a compensation system is employed in a binocular, a pair compensation lenses are moved in a direction perpendicular to the optical axis of each telescopic optical system. In such a type of the compensation system, two compensation mechanisms should be provided, which are:
(1) a mechanism for moving the compensation lenses in a vertical direction, i.e., an up/down direction when the binocular is held horizontally; and
(2) a mechanism for moving compensation lenses, which are also provided within the optical paths of the telescopic optical systems, in a horizontal direction, i.e., in a right/left direction when the binocular is held horizontally.
For the mechanism which moves the lenses in the vertical direction, it is necessary to change a response speed and/or voltage or electrical current for an actuator, depending on whether the lenses are moved in a direction of the gravity or in the opposite direction. In other words, controlling of the mechanism for moving the lenses should be changed when the lenses are moved in the vertical direction, and accordingly controlling is relatively complicated.
Further, such a mechanism is required to have a driving device which has a relatively large torque in order to move the structure with resisting the gravity, and a relatively large battery for supplying sufficient power to such a driving device. Therefore, the compensation mechanism becomes relatively large.